Revisiting the USPTO Concordance Between the U.S. Patent - PDF document

Revisiting the USPTO Concordance Between the U.S. Patent Classification and the Standard Industrial Classification Systems Jim Hirabayashi, U.S. Patent and Trademark Office The United States Patent and Trademark Office (USPTO), with support from the National Science Foundation, has maintained and updated a concordance between the U.S. Patent Classification and Standard Industrial Classification Systems since 1974, when it was created. The high-level, general concordance is intended as a means to aggregate patent data by a standardized classification system for which a variety of economic and other statistics are routinely collected and made available. The USPTO concordance relies on a manual review and mapping of USPC subclasses to selected, high-level SIC classifications that are generally at the two to three digit SIC level. This paper presents a view of the underlying methodology used to construct the concordance, compares it with some other recently used concordance methodologies, and discusses some of the considerations regarding the accuracy and relevance of the concordance. 1. Introduction During the last twenty-five years, patent data have received increased attention and use, particularly as an indicator in research involving innovation and technological activity. Patent data are attractive for many reasons. They represent technological innovations that have met a defined standard as required for patentability; they are associated with a wide range of technologies; they are available for an extensive and continuing time period which, in the case of U.S. patent grants, spans over 200 years; they have been classified into detailed technological categories that facilitate aggregation of the data; each patent grant identifies the owner, inventor, geographic origin, technology, issue date, application date, and other information associated with the patent to assist in describing and characterizing the technological activity associated with that patent; time-series data are available in electronic format for patents granted in recent years which facilitates computer-aided quantitative research studies; U.S. patent grants, in addition to reflecting domestic technological activities, also reflect a wide range of foreign technological activities as a result of the importance of the U.S. market and the desire of applicants to obtain patent protection in that market. There is, however, a fundamental difficulty in using patent data and economic data together in quantitative research studies, for example, studies that seek to define relationships between economic growth and technological activity. This difficulty stems from differences in the ways that patent data and widely available economic data are collected, classified, and made available. 1

Economic data tend to be collected, classified, and made available by categories based on industry classification systems such as the Standard Industrial Classification System (SIC), the more recent North American Industry Classification System (NAICS), and the International Standard Industrial Classification System (ISIC). By contrast, the United States Patent and Trademark Office (USPTO) primarily relies upon the U.S. Patent Classification System (USPC) to classify U.S. patent documents. Many other countries rely on classification systems that are based on the International Patent Classification System (IPC) to classify their patent grants. Unlike the classification systems used to collect and disseminate economic data, these patent classification systems, for the most part, are based on the function or structure (e.g., chemical formula, layered product, gear, etc.) of the patented technology and not on the associated industry of manufacture or sector of use. One way to make industry-based classification information available for each issuing patent would be to review each patent and to associate it with its corresponding industry-based category or categories. Such a method would allow for patents to be classified according to industry of manufacture, sector of use, or any other appropriate industry categories. However, perhaps for reasons such as budget and staffing constraints, this kind of individual patent review and classification by industry generally has not been adopted by national patent offices with the notable exception of the Canadian Patent Office, which included the classification of patents by industry for patents issued between 1976 and 1993 (1) . 2. USPTO's USPC-SIC Concordance Brief History and Overview The original USPTO concordance between the U.S. Patent Classification System (USPC) and the Standard Industrial Classification System (SIC) was developed in 1974 with the support of the National Science Foundation (NSF) to attempt to bridge the gap between the industry and patent based classification systems associated, respectively, with economic and patent data. This concordance, often referred to as the "OTAF Concordance," was developed by manually reviewing classification categories in the USPC and associating them with a limited set of industry-based product fields based on the 1972 SIC. See Table 6 for a list of these industry-based product fields. This USPC to SIC Concordance is maintained by USPTO's Patent Technology Monitoring Division. It is based on the industry of manufacture and is updated on a regular basis, generally annually, to accommodate changes and revisions that are made to the USPC each year. To update the concordance, changes (including additions, deletions, and modifications) to the USPC are manually reviewed, new entries added, outdated entries removed, and, where necessary, existing entries revised. The most recent update available for the USPC to SIC Concordance applies to the USPC as it existed as of December 31, 2001. Substantial detail relating to the Concordance development process was published in a review that was initiated with NSF support. The review included an internal study of 2